In conventional conveyor belt installations of which the Applicant is aware, a continuous conveyor belt is mounted to be supported and guided by a plurality of cylindrical idler (which may be either freely rotatable or driven by a drive mechanism). Such idlers typically comprise a central metal axle and a hollow cylindrical polymeric sleeve mounted by means of bearings to rotate about the axle. An exterior surface of the sleeve provides a bearing surface to bear against (and usually to support) a conveyor belt thereon. The axle projects axially outwardly past either end of the sleeve to provide mounting lugs at ends thereof.
A drawback that the Applicant has noted is that the sleeve tends to deform over time. This deformation is more pronounced under heavier loads or harsher operating conditions. In addition, if the conveyor belt is stopped and the idler is required to support a stationary load, this also causes deformation of the polymeric sleeve. More specifically, under moving (rolling) conditions, the sleeve tends to develop a concavity (usually symmetrically) which is most pronounced around its mid-portion. This is due to the constant inward force exerted by the conveyor belt. When the belt is stationary, the weight of the belt will be in a fixed direction, causing the idler to deform (usually asymmetrically) away from the belt.
This deformation is caused, in part, because the idler (specifically the sleeve) is hollow. However, it is hollow of necessity—having a solid sleeve would render the idler impractically heavy and prohibitively expensive. Accordingly, the Applicant desires an idler which at least partially overcomes these drawbacks and advantageously is more resistant to deformation and may optionally provide additional benefits.